I had exactly the same problem with the xml_id in a
totally different scenario, when I was trying to change
the layout of Invoices through the view inheritance
facilities. There is no way through the UI to get an
xml_id :-( You basically will need to do it manually
through the backend files in the addons directory.

I'm going to raise this issue with Odoo separately because
it's really limiting some of the features.

Going back to your problem, can I ask you what version of
Odoo you are using? I have documented how to set up UK
accounting in Smart Mode for V8, but that's probably not
relevant to you, although the process should be the same
(or very similar).

Have a look if you like. Just remember it's not for
commercial use, we've done this for our own information.

I would like to know how other partners are managing
the setup of account module. My question is related to
the fact that when you install the module, even if you
choose you chart account the default one is created
and you have to manually deleted. Also notice that the
account chart template only work from a specific
follow of installing the module.

Another thing is related to the account journal. I
believe that is created by code, because there is no
xml_id and I can't find and xml with that data, to
allow me to setup all the journal when I install my
account localization. That would avoid the need that
every time you install this module you have to delete
setup manually the journal, delete the account and
taxes and default account chart.